Enlargement of Neural Foramina and Dynamic Stabilization in Spondylolisthesis without Restoring the Alignment: Technical Note

It is well known that the cause of radiculopathy is the compression of the nerve root within the foramina which is narrowed secondary to sliding of the corpus and reduced disc height. In some patients, unroofing the foramen does not resolve this problem. We described a new decompression technique using pedicle removal and transpedicular dynamic instrumentation to stabilization the spine. We performed this operation in 2 patients and achieved very good results.

Individualized localization of the lumbar pedicle screw entrance points by vertebral plate borderline / 中国矫形外科杂志

[Objective] To investigate the effectivity and reliability of individualized method to localize the entrance point of the lumbar pedicle screws by vertebral plate borderline.[Methods]Four vertebra specimen were taken the X-ray film of anterior-posterior views as the center of L2.On the X-ray film,the distance between the centre-point of the pedicle to the lateral and superior margins of the vertebral plate were measured,after applied barium at the centre-point of the pedicle,the specimen were taken the X-ray film once more,the relation of the barium to the centre-point of the pedicle was measured;the distance between the centre-point of the pedicle to the lateral and superior margins of the vertebral plate were measured on the normal lumbar X-ray film in 107 cases,the data in different sex and different projection 's center were compared;the method were applied to 40 patients of lumbar pedicle internal fixation,the information in hospital were reviewed to 30 patients of the lumbar pedicle screw localization by transverse process and transverse process.[Results]All(except L5)of lumbar plate borderline were displayed clear in the experiment,accurate rate of setpoint to be 92.5%.The principal X-ray affected scarely to the relation of the pedicle with the plate borderline of nearby two segment,but affected obviously far from three segment on the normal lumbar X-ray film;the accurate rate of one time 's setpoint in clinical application was 96%,average operation 's time being 96 minute,average lose blood being 212 ml,transverse articular process 's group showed significant difference.[Conclusion]Individualized localization of the lumbar pedicle screw entrance points by vertebral plate borderline is one of feasible method,displayed less trauma and accurate rate highly in the clinical application.

Morphometric Study of the Pedicles of Lumbar Vertebrae in Koreans

OBJECTIVE: This study was undertaken to study pedicle morphology in Koreans to provide a reference guide in transpedicular screw fixation. METHODS: Pedicle measurements were obtained from 35 dried human lumbar columns(175 lumbar vertebrae). Anatomic evaluation was focused on pedicle transverse diameter, pedicle axis length and the distance from the pedicle axis point to the midline of the transverse process. Pedicle angle and vertebral body length also were measured. RESULT: In the transverse plan, pedicle diameter increased from L1(7.8mm) to L5(15.5mm). But in 20.0% of L1 and L2, its diameters was under 6.0mm. In the sagittal plan, it was not as constant and had similar diameter from L1 to L5. In the transverse plan, the pedicle angle increased from L1 to L5. But in the sagittal plan it decreased from L1 to L5. Also, the pedicle axis length did not show concordant change, but rather had similar length in lumbar vertebrae. In 15%, its length was under 45mm. CONCLUSION: These results suggest that using above 6mm diameter and 45mm length of screw for L1 and L2 can violate the pedicle and vertebrae. Above L4, the pedicle axis point was superior to the midline of the transverse process, below L4, it was inferior to the midline of the transverse process. This information may prove to be helpful when contemplating the placement of screws to the lumbar pedicles.

Morphometric Analysis of the Pedicle of Lumbar Vertebrae Based on Radiologic Images in Koreans / 체질인류학회지

The vertebral pedicle is an important structure used as an implant site for spinal instrumentation surgery. Since precise anatomical knowledge of lumbar pedicles in vivo is essential for risk - free surgery, we analyzed Korean vertebrae with radiologic imaging techniques. The authors analayzed 500 pedicles from L1 to L5 vertebrae with computerized tomograms (CT) and simple radiograms taken from patient free of vertebral abnormality. Five morphometric parameters: transverse pedicle width, transverse pedicle angle, sagittal pedicle width, sagittal pedicle angle depth to anterior cortex were measured. The transverse diameter and angle of pedicle increased gradually from L1 to L5, while the sagittal diameter and angle decreased from L1 to L5. The depth to anterior cortex from posterior elements was longer along the pedicle axis than along axis parallel to midline.

Analysis of Morphometric Characteristics of Lumbar adieles

During the past decade, internal fixation techniques for stabilization of spinal fracture, correction of spinal deformity and immobilization in degenerative spinal diseases have increased in general, pedicle screw fixation of the spine provides the three dimensionally rigid grip on each vertebra and minimizes the levels of spinal segment that is needed for proper fixation. But with the increasing use of pedicle screw, there is an increase in incidences of complication. Major complications of pedicle instrumentation are screw malposition, pedicle fracture, iatrogenic foraminal encroachment, injury to the facet joints or vessels, and mechanical failure. These complications may be associated with irreversible damage of both vertebral and neural elements. Therefore, full understanding and knowledge of vertebral morphology is essential for proper instrument fixation and avoidance of complications. A total of 500 pedicle measurements were made from L1 to L5 vertebra. Five morphometric parameters were studied, transverse pedicle width, transverse pedicle angle, depth to anterior cortex, sagittal pedicle width, sagittal pedicle angle. Measurements were done using both spinal computed tomography and simple lumbar X-rays. As for the results, the means of transverse pedicle width is 7.9-16.6mm, transverse pedicle angle is 8.3-29.1 degrees And depth to anterior cortex is 43.8-47.9mm. The results were compared with previous data.